Science

6:49 pm

Thu May 23, 2013

'Extremely Active' Atlantic Hurricane Season Predicted

Hurricane Sandy churns off the Atlantic coast on Oct. 29. NOAA officials are forecasting seven to 11 hurricanes, compared with about six in a typical season.

NASAGetty Images

Unusually warm ocean temperatures and favorable wind patterns mean the Atlantic is likely to see "an active or extremely active" hurricane season this year, say officials from the National Oceanic and Atmospheric Administration.

The agency expects between seven and 11 hurricanes and as many as 20 named storms during the 2013 season, which runs from June 1 through November.

So for residents of the Atlantic and Gulf coasts, "now is the time to pay attention to preparedness," NOAA's acting administrator, Kathryn Sullivan, told a news conference Thursday at the agency's new Climate Prediction Center in College Park, Md.

Extreme weather can be deadly, Sullivan and other officials at the event stressed. "Our hearts go out to the people in the communities in Oklahoma, who as we join here today to talk about hurricanes, are still recovering from Monday and Tuesday's devastating tornadoes," Sullivan said.

Tornadoes, like the one that ripped through Moore, Okla., can produce winds that are more intense than those of hurricanes. But hurricanes generally cause more damage and loss of life because they can cut a swath of destruction that is hundreds of miles across.

In an average year, about six hurricanes and 12 named storms form in the Atlantic Ocean and Caribbean Sea. But this year is likely to be more active than normal for at least two reasons, say forecasters.

One reason has to do with the temperature of the water where hurricanes tend to form. "The tropical Atlantic is very warm, much warmer than normal," says Phil Klotzbach of Colorado State University. "And since hurricanes live off of warm ocean water, we expect to see more tropical cyclones and probably more intense [ones] than an average season."

Another factor is the lack of so-called El Nino conditions, which occur when waters in the tropical Pacific heat up. An El Nino tends to produce wind patterns that tear apart Atlantic hurricanes as they approach the U.S.

Last year at this time, many forecasters believed an El Nino was on the way, says Dan Leonard of Weather Services International. "And then in reality, El Nino wasn't as strong as we initially thought."

So there were lots of storms, including 10 hurricanes. But most of them turned away from the East Coast as they encountered strong winds from the jet stream, Leonard says.

Government forecasters say it's hard to know whether those winds will continue in 2013. But Leonard says he sees some evidence that they will.

"We think we'll have a pretty active jet stream, and that should deflect a lot of these storms back out to sea," he says, adding "that's not to say that one can't sneak through as we saw happen last year with Sandy."

Sandy struck the New York and New Jersey coast in late October and became the second-costliest hurricane in U.S. history. At the NOAA news conference, Sullivan urged people to think back to that storm as they prepare for the upcoming season.

"With the devastation of Superstorm Sandy fresh in our minds and another active season forecast," Sullivan said, "we again encourage families and businesses in states along the Gulf and Atlantic Coast and inland from those areas to take time now to make or refresh their hurricane preparedness plans."

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Transcript

ROBERT SIEGEL, HOST:

You're listening to ALL THINGS CONSIDERED from NPR News.

The Atlantic hurricane season begins just over a week from now, on June 1st. And today, government officials urged the public to prepare for what's expected to be a busy one.

NPR's Jon Hamilton reports.

JON HAMILTON, BYLINE: The officials unveiled their seasonal outlook at the National Oceanic and Atmospheric Administration's new prediction center in College Park, Maryland. Their message was: Extreme weather can kill.

Kathryn Sullivan is acting administrator of NOAA.

KATHRYN SULLIVAN: Our hearts, first of all, go out to the people in the communities in Oklahoma, who as we join here today to talk about hurricanes are still recovering from Monday and Tuesday's devastating tornadoes.

HAMILTON: Tornadoes can produce winds that are more intense than those of hurricanes, but hurricanes generally cause more damage and loss of life because they can cut a swath of destruction that is hundreds of miles across. And Sullivan says forecasters expect this season to produce a lot of hurricanes and tropical storms.

SULLIVAN: NOAA predicts an above-normal and possibly an extremely active hurricane season with a range of 13 to 20 named storms. Of those 13 to 20, we predict that seven to 11 will become hurricanes.

HAMILTON: That compares with about six in a typical season. In 2012, there were 10 hurricanes, but it was the last one, Sandy, that caused huge damage in New York and New Jersey. Sullivan urged people to think back to that storm as they prepare for the upcoming hurricane season.

SULLIVAN: With the devastation of Superstorm Sandy fresh in our minds and another active season forecast, we again encourage families and businesses in states along the Gulf and Atlantic coasts and inland from those areas to take time now to make or refresh their hurricane preparedness plans.

HAMILTON: Especially their plans to evacuate, if necessary. Forecasters from NOAA are just the latest to predict a perilous 2013 hurricane season. For more than a month now, others have been weighing in.

(SOUNDBITE OF WEATHER REPORTS)

MATT SAMPSON: And from the looks of things, it's going to be a busy season.

JOE BASTARDI: So we are expecting a very active season.

DAN LEONARD: Probably a little bit more intense with the storms this year.

PHIL KLOTZBACH: About 175 percent of the average hurricane season, so about 75 percent more activity than normal.

HAMILTON: That was Matt Sampson of The Weather Channel, Joe Bastardi of WeatherBELL, Dan Leonard of Weather Services International and Phil Klotzbach of Colorado State University. There are a couple of reasons that all the experts seem to expect a busy year.

Klotzbach says one reason is measurements showing unusually high temperatures in the waters where hurricanes tend to form.

KLOTZBACH: The tropical Atlantic is very warm, much warmer than normal. And since hurricanes live off of warm ocean water, we expect to see more tropical cyclones and probably some - more intense than an average season.

HAMILTON: Another factor is the lack of so-called el Nino conditions. El Nino tends to produce wind patterns that tear apart Atlantic hurricanes as they approach the U.S. And Dan Leonard of Weather Services International says last year at this time, it looked like an el Nino was developing.

LEONARD: So last year, we thought, OK, el Nino might come on, and that would inhibit the amount of activity in the Atlantic. And then in reality, el Nino wasn't as strong as we initially thought.

HAMILTON: So there were lots of storms. But last year, most of them turned away from the East Coast because they encountered strong winds from the jet stream. Government forecasters say it's hard to know whether those winds will continue in 2013, but Leonard says he sees some evidence that they will.

LEONARD: This year, we think actually it will be very similar to years past where we'll have a pretty active jet stream, and that should deflect a lot of these storms back out to sea. Now, that's not to say that one can't sneak through as we saw what happened last year with Sandy.

HAMILTON: Which struck the coast in late October and became the second costliest hurricane in U.S. history.